Two explanations for collective behavior were contrasted. The first, exemplified by relative deprivation theory, stresses the importance of feelings of moral outrage and perceived economic injustice. The second focuses on more pragmatic considerations, such as the availability of resources for mobilization. The present study examines these explanations for collective behavior in a laboratory setting. Subjects were members of a disadvantaged group. In a 3 × 2 factorial design two independent variables were manipulated. The magnitude of pay inequality between the disadvantaged group and a more advantaged group was manipulated to be large, moderate, or small. Mobilization resources available to the disadvantaged group were manipulated to be either present or absent. In accord with predictions based on relative deprivation theory, as the magnitude of the inequality increased, stronger feelings of deprivation were expressed. However, contrary to relative deprivation theory, larger magnitudes of inequality and stronger feelings of deprivation were not associated with greater willingness to engage in legitimate or illegitimate forms of collective behavior. Instead, as predicted by some critics of relative deprivation theory, willingness to engage in illegitimate forms of collective behavior was affected only by a pragmatic consideration: the presence or absence of mobilization resources.